It looks to me like the 0.5uR is bringing Toby down more than 100 points, which might be more than you want it to. You want the Lev to be providing most of the action and the R to just be tweaking.
For example, looking at 2/17, with no R in the am, Toby only dropped 52 points from amps to +3, which seems to be fairly typical for him.
That evening, with 0.5uR he dropped 139 points by +2.
Today he's dropped 92 points by +2 with the 0.5uR.
Overall, his ss is looking pretty good, however. The thing to be aware of is that if the R drops him too fast, it can cause a bounce in response. Then he may be higher at the next shot time than he otherwise would've been. It can become a viscious cycle. I don't think you're in that at this point, I'm just mentioning it for you to be aware of. Most of the time people think in terms of moving the cat 50-100 points max - the goal being to lower the blood sugar so that the Lev can work better. Both Lantus and Lev do much better controlling lower blood sugar than high blood sugar.
Using R is a bit of an art - we don't have an exact formula that fits every cat. But I think you are doing fine overall. You're seeing blue almost every cycle with him, which is pretty good. Let's tag
@Sandy and Black Kitty and see if she has some thoughts to suggest for you.
As far as your Lev dose, I would increase it and let it do most of the heavy work on the blood sugar for you. When you get to the point that you're depending on R to have those blue numbers, that's a good indicator (to me, at least) that you need to increase the Lev. When you're increasing, consider that the protocol suggests a 0.25u increase on a 1.0-3.0u dose. That's an increase of 8%-25%. At 16.5u, a comparable increase is 1.32u-4.1u. Double-check my math but i think that's correct. I think in terms of a 10% - 25% increase, depending on how much you need to move the kitty's BGs. In Toby's case, right now, he's got a lot of blues so I would think more along the lines of 10% increases, so perhaps moving him from 16.5u to 18u (increase of 1.5u, just less than 10%).
When you increase the Lev, I'd hold off on the R so that you don't give a double-whammy that you didn't mean to give!
Anyway, that's something for you to consider.